The present invention relates to a lip-film formulation which provides a thin, flexible, water-resistant film when applied to the lips and allowed to dry. The lip-film thus formed is long-wearing and does not smear or bleed.
Commercial lip color is generally supplied as either a lipstick or a lip gloss. Lipsticks are blends of waxes, oils, and colorants which are mixed together and then melted and molded to form a stick. Lip gloss is a semisolid mixture of wax, oils, and colorants containing relatively less wax than a lipstick formulation.
When applied, both lipstick and lip gloss remain in a semi-solid state. This results in the need for frequent reapplication to maintain the desired cosmetic effect, as the lipstick or gloss is worn off in the course of eating, drinking, smoking, or just talking. Lipstick and lip gloss are also prone to smearing, and can cause hard to remove stains on clothing.
Lip films have been described in the literature, but they either do not address the above problems, or have other disadvantages of their own. U.S. Pat. No. 2,230,063 describes a lip film composition in which ethyl cellulose was used as a film former in an ethanolic solution. This led to a moisture-proof, smear-proof film, but the application of ethanol to the lips was found to be unacceptably irritating and drying.
U.S. Pat. No. 3,122,481 used methyl cellulose to form a lip-film based on an aqueous solvent. This addressed the difficulties posed by the ethanol of U.S. Pat. No. 2,230,063, but did not produce a water resistant film. Methyl cellulose is readily water soluble and, therefore, the resulting films did not wear well, since they were rapidly dissolved when contacted with aqueous liquids, e.g., saliva or beverages.
Other patents also describe lip-film formulations. U.S. Pat. No. 2,548,970 makes use of gum benzoin and cetyl alcohol to form a lip film. U.S. Pat. No. 3,088,876 teaches lipsticks in which film forming rosin or rosin derivatives and wax are dissolved in a solvent. Both of these patents rely on alcohol or other organic solvents, however, and therefore have problems with drying and irritation.
Film-forming acrylate resins are known which produce films which are water-resistant, yet which are soluble in basic aqueous solution. U.S. Pat. No. 3,590,118 teaches the use of such a resin as a film-forming carrier for insect repellant. These resins have also been proposed for use in a variety of cosmetic applications such as body paint and eyeliner. They have not been used, however, in lip-coloring formulations which require an unusually high degree of plasticity due the extremely high mobility and irregular surface contours of the lips. Formulations for other cosmetic applications are generally unsuitable for lip-coloring applications and would tend to crack and peel as the lips move.
It is the object of this invention to provide a water-based lip-film composition which provides a comfortable, long-wearing, water-resistant film for use in applying colorants or medication to the lips.